Hi Dean, as I understand it Minco’s original aim was to prove mineralisation in the Melmerby Scar Limestone, which is one of the thickest of the Carboniferous limestone series.
Unfortunately they did not find anything easily in this strata, and then put all their efforts on re-examining the Great and little limestones.
They found some marginal deposits but not the large deposits that modern mines need in order to establish a new processing plant.